This invention relates to a reference voltage generator which is constructed of MISFETs (insulated gate type field effect transistors).
Two MISFETs whose gate electrodes are made of materials having work functions different from each other exhibit threshold voltages different from each other. The difference between the threshold voltages of the two MISFETs becomes equal to the difference of the work functions of the gate electrodes in the respective MISFETs. The threshold voltage difference can be utilized as a reference voltage. Since the reference voltage thus obtained has its value determined by the work function difference of the two gate electrodes, it is less liable to evil effects attributed to dispersions in the characteristics of the circuit elements.
Accordingly, when fabricated in the form of an integrated circuit, a reference voltage generator utilizing the work function difference produces a reference voltage of comparatively precise value in spite of comparatively great dispersions in the characteristics of various circuit elements in the integrated circuit.
The inventor's researches, however, have revealed that the reference voltage exhibits a temperature dependence and a supply voltage dependence which are not negligible.